Jig saw



' Sept; 11, 1923.' www@ W. A. FIELD JIG SAW Filed June 25. 1921 3Sheets-Sheet 1 '1,65* iff/71j 2* y rig i? ze EAW'Z@ 3 Sheets-Sheet 2Sept. l1, 1923.

A l w.`A. FIELD v J'IG sAw Filed June 25 1921 Sept' 1l, 1923.

w. A. FIELD TIG SAW i 5 Sheets-Sheet 3 l IEE Filed June 25 1921 PatentedSept. 11, 1923.

Lierre perron.

WlfllrlhMl` A. FIELD, OF CHICAGO, ILLINOIS, ASSIGNOR TO-VM; A. FIELDCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

Y Application ,filed 'unefZ-i, 1921. Serial No; 480,321.

To all fwzomiz'zf may concern: v

- Beit known that I, VILLIIM A. FIELD, acitizen of the United. States,anda resident otlsChicago, in the county otCook andV State. oflIllinois, have invented `certain, new a11d,.useful Improvements in JigSaws, of which the following` is a speciiication, reference-,being hadto the accompanying drawings: Y

l() My invention relate'sto saws and has for its objects to provideimproved means Jfor holding and actuating the saw bladev so thatit willalways,befmaintained 4under proper'tension, on the upstrolre aswell ason l5 the downstrolrmsalso to provide ior readily i removing andreplacing the'saw blades ;v to

' provide' meansrby Whiclithe machine may `readily. beadjusted -1toaccommodate'sa-W =b-lades'of different lengths; and also topro- 2.0fvide a power-driven'jig saw Withfmeans 'operating to` stop. the machinethe sasvr blade should break= or become disconnected. 'I ac-`complishthese objectsras illustrated in the accompanying drawings andvhereinafter Ade- 25 scribed. :lhat I` regard asnew is set forth 'inthe'claims. -Y i j In theaccompanying draWings,--v

' Y Fig.lV is aside elevation of my improvedl machine, some partsrbeingshownV insecf 310 tion;

Fig; 2 is an enlarged detail, being, a partialsectional view on `line'2,-2' ofV Fig. 1,Qill ustratinga partY otthe driving chain Vor belt;,.

Y '35 Fig, 3 Vis arg-front "viewvof the machine,rthe

housing-Which encloses certain parts o-'the operating meclianismbeingbroken away;

'Y Fig/1C is a horizontal section on line 1 -4t 40 Fig. ,5. is anenlarged'partialv vertical sectionjorl line 5-5 of Fig.Y 3;

5.5 l. Referring to thedraWingsf-A'll indicate-3 'Y Fig. Gisanjenlarged' front view ot theV the base or main vp'ortionof-the machineframe .which is of suitable size and 4sli-ape to support the other partsthereof., Said base carries a table or Work` supportfl2 having a slot 13Jfor the passage ot the saw blade, and is provided with ahollovframe orhead le having a, latemily-extending arm 15v which overlies thetable1'2, as shown in, Fig. 1. The head 14 is vertically adjustable Withreference tothe base 11, and to this-end .it is provided withverticallydisposed laterally-projecting beveled anges 16 which areadapted to Vslide in guidivays provided4 at the back of the base, asbest shownV iirFig. 4. AThese guideways are Y formed by providing guideplates`17V which 'the head 1 4, and it Will be apparent, therefore, thatbyV rotating said scrervitr will be causedto travel through theboss2l,thereby correspondingl'y` moving thehead 14C.V

At the front of the machine the base 11 is provided withavertically-disposed guide 22 in Whichis iitted a sliding block forcross- Ahead 23 having at. its upper endy'a bifurcated hook 24 adaptedtoengage the usual crosspin 25 carried` at the lower endjbf a jig sauTblade 26, vas shown inFi-gs. 6- Vand. As shovvninthe latter igure,thehook 24 is.A provided With-a threaded shank 27 which passes through aboss 28 projecting laterally from thecross-head 23. A nut 29 is screwed'on Vthe lovver end ofsaid shank, and' a lock nut y30 1s provided onsaidshanlrabove the `boss 28 so thatthe hojolr 24 may be firmly securedto saidboss,Y by which construction the hook v24.` may be adjusted withrelation to the cross-head or may readily be. removed when desired. Ifnthe operation of the machine the cross-head23 is reciprocatedverticallyby means of a pitman 31, the upper end of.r which isconnected` to aWrist pin 32 carried by the cross-head', while itslower end is connectedtoz awrist pin 33 eccentrically carried by a gear 3.4 which isV journaled yeo upon a stud 35 which projects laterally from the base 11,as shown in Figs. 1 and 3. The gear 34 is driven by means of a pinion 36mounted on the armature shaft37 of an electric motor 38 which ispreferably mounted in a suitable chamber provided for that purpose inthe hollow base 11. 39 indi-v cates a cover-plate for enclosing suchchamber, as shown in Fig. 1.

The upper end of the saw blade 26 is held bya .hook40 somewhat 'like thehook 24, which is secured to an upper' cross-head 41 mounted similarlyto the cross-head 23 in f a suitable guideway 42 provided for thatVpurpose in V.the outer endf portion of; the arm 15, as best shown inFigs. 1 and 5.

vilVhen a saw blade has been applied to the machine it is held underproper tensionand iis reciprocated by 'means of a chain or flexible belt43, one end of which is connected to the upper cross-head 41, as shownat 44 in Fig.- 5, while the other end thereof is connected with thelower Y cross-head 23 by means of ya bolt 45 which passes looselythroughV la boss 4G carried by the cross-head 23 and has a nut 47screwed upon itsupper fend as shown in Fig. 7. 4'8'indicates a springwhich is mounted on the bolt 45 between the I* Vboss 46 and the nut 47,a collar 49 vpreferably being interposed between said nut and the upperend of'said spring. The 'intermediate Vportion ofthe belt 43 issupported by means of rollers 50, 51, V52, 53 and 54arranged as showninFig. 1. rEhe rollers 50, 51 and 52 are carried by the head 14 and movewith it Y when it is adjusted vbymeans ofthe adjust ing screw 19. `Theroller 54 is mounted in the base`f11 adjacent to the lower.cross-headV23 and it is in the'same verticalplane as the roller50. The roller 53 ismounted at one end portion of a rocking arm55 which is pivoted in thebase: 11 upon the pivot 56. The opposite 'end of said arm extends intothe head 14and' is forked as shown at 57 to ,receive a pin 58 carried bysaid head. By

this arrangement, when the head 14 is ad'- justed vertically itrocksltheA arm `and vertically adjusts the roller53. As the belt -43passes over said roller and under rollers which isnot materiallyaffectedby the operation of the machine, since when the pitman V31 movesupward to carry thesaw blade in the saine direction it also moves thelower end ofl the chain 43 upward,vthereby transmittinga correspondingupward pull to the cross-head 41 to which the upper end of the saw bladeis attached; Onthedown stroke: ofthe blade vthe'chain 43 movescorrespondingly in the opposite direction. The result is that the sawblade is kept under proper tension o n its up'stroke as well as on Vitsdown stroke, thereby making it operate more smoothly and avoiding dangerof buckling the` saw. 4 Y

V Vi/Then a sawblade is tov be removed or replaced itisnecessary torelai;- the'tension on the upper portion `ofthe chain 43 until that workis accomplished, and Alin Amy' improved machine this may be accomplishedeither by hand or by footv power.' At the upper part of Fig. 11'haveillustrated a handlever 59 for this purpose, said lever beingmounted on a fulcruin 6() and being provided with a Finger 61 which isadapted,

bv the swinging of said leverin the 3ro er n n direction, to engageablock 62 carried by the chain 43, as best shown in Figs. 1 and 2.

This block is mounted onl ascrew-'threaded tubular bolt G3Ywhich isconnectedto one of the links and receives a rod 64 telescoped Vthereinand 'adapted to be 'held against llongitudinal movement by across-pinVvG5 which passes through said; rod and through suitable holesprovidedfor that purpose in the bolt 63.4 Theblock ,6.2 is preferably providedwith a recess inA one of its faces to receivethc cross-pin 65, as shownFig. 2, thereby locking said crossepin Vin position.

rlhe length of 'the connection formed bythe rod 64 and bolt 63 may bevariedby pro- I Yviding the rod 64 with a plurality of holes YYarrai'iged to recive the pin 65 as indicated 1i'iyl-dotted lines insaid ligure. `From aninspectionwof Fig. 1 it will be seen that. by

swinging the lever 59 'to the right the 'finger 61 may be caused toengagethe block 62and exert a pull in the same direction upon the chain43` against the tension'` of the spring 43, thereby allowing the hook 40to be moved toward the opposite' hook 2 4 sufficiently to permit a sawblade to be putin pla-ce or removed.- Vhen this operation is performedthe hook `24 does not movek downwardly'un der the strain owing to thefrictionalresistanceof-the motor. While l prefer toequip the chain43with a connection such as that shown in Fig. 2,-rnyinvention'contemplates theuse of any other suitableineans by Awhich thelever 59.1nay be `caused to engage; and

operate the chain 43 in the manner` described.

ln order that this `workmay be done by foot power if desired, l also`provide a foot lever G6 which is fulcrumed at 67 on the base 11,

and is connected by a rod 68 ,with a lever 69 V fulcrumed at 70 on theupper portion of the base, as shown in Fig. 1. rlhe opposite end of thelever-69 is connected by a flexibleconnection 71 running over apulley 72with an Cil arm 7 3 carried by theilever 59 or fulcrumed on the pivot60. By this'mea'ns when the foot'lever 66 is depressedtlie finger 61will be actuated in the manner already described to move the upperportion of the chain .43 to the right and move the hook 40 down intoposition for releasingthe saw blade 26 already in place, or to receive afresh blade.

If the saw blade should break while the machine is in use itis.desirable that the operating mechanism .be stopped automatically, and tothis end- I` provide vIa switch shown inFigures l, 9 and 10 whichcontrols the operating circuit/of the motor 88, and

which is arranged to be automatically opened VVto break such circuit ifthe saw blade should break or` bepome disconnected. In the constructionshown I employ for this purpose an ordinary knife blade switch 74``which ispivoted at. 7 5 adjacent to an intere' mediate portion ofthefjchain-Aij' and fis'provided with an arm` 76 and a spring 77. iQneend of saidspring isconnected with the arm.

76 and the other end with the` frame V14 so that said 'spring tends toVmove the switch 74 out 'of operative "engagement with' co'- actingcontacts 78, 'as best shown in Figx9.

The switch. 74 is heldin position to close the motor. circuit by a latch-79 which is mountedon a pivotl 80 supported'by the frame of themachine, and is provided with an arm 81 having a sleeve 82whicnleinbraces lthe chain43, preferablyat a point where a coupling 83such as that shownin Y Fig. '2 is provided. The chain and coupling movefreely through the sleeve 82, but" the sleeve 82 is adapted to beengaged by va block 84 carried by said 4coupling :if the chain Vshouldmove down beyond its normal rangef of movement. The'spring 48 shown inFig.

v7 tends to pull downward on the portionof the' chain adjacent tothelatch 79, and, therefore, if the, sawblad-ef should break or becomedisconnected said spring willrmove the intermediate vportion of thechain 43 Vdown far enoughto Vcause `the block 84 to engage the arm 8l4of the lever 79 and move y it downward far enough to release the switchscription, when the saw blade is in placeit forms with the chain' 43 anendless belt which. moves back and forth over the sup-l porting pulleys,during which operation thel tension on the saw blade is maintainedpractically uniform at all times, as it makes the operation of themachine much smoother and better and minimizes the danger "of breakingthe saw. Y

`Vhat I'claim as my invention and desire to secure by Letters Patent,is-

. for detachably engaging and Amovingone end portion of said belt inopposition to the tensionV of Said spring. Y

2- A jig saw comprising a machine frame, a belt'supported by said frameand adapted to beconnected to the opposite ends of a saw blade, guidesfor vthesaw blade, a spring operating to hold said belt undertension andconnected between the driving means and the adjacent end of the belt,and a lever havingV an.v arm movable into engagement with said belt formoving one vend portion thereof against the tension of said spring.

3. A jig saw comprising a machine frame, a belt supported by said fra-meand adapted to be connected tothe opposite ends of a saw blade, guidesfor the saw blade, a spring operating to hold said belt under tensionand connected between the driving means and theadjacent end of the belt,and hand ,and foot levers for detachably engaging and Vto of one end ofVa saw blade, a guide block mounted on said arm in alineinent with saidcross-head, andY having means 4for the attachment theretoof the otherend of the saw blade, a belt connected with said cross-h`ead and guideblock, guides for said belt,.and means for adjusting said belt tocompensatev for theadjustinent of said adjustable head. 5. A jig sawcomprising a base, a head adjustably mounted on said base and having Vanarm extending over said base, a recipro eating cross-head mounted on thebasand having means for the attachment thereto of one end of asawj'blade, a guide block mounted on said arm in alineinent with saidcross-head, and having meansfor the at'- tachinent thereto of the otherend of the saw blade, a belt connected with said crosshead and `duideblock, guides for said belt, and compensating means operated by theadjustment of said adjustable head for correspondingly adjusting saidbelt.

A saw comprising a base, a head adjustably mounted on said base andhaving an arm. extending over said base, a reciproeating cross-headmounted on the base and having means for the attachment thereto of oneend of a saw blade, a guide block mounted on said arm in alinement withsaid crosshead, and having means for the attachment' thereto of the`other end of the saw blade, a belt connected with said cross-head andVguide block, guides 'for said belt, a lover mounted on the base, aguide for said belt mounted on said lever, and means operated by theadjustment of said adjustable head for rocking said lever to makecompensating adjustment of said belt. i

7. A saw comprising a machineV frame, a belt supported by said frame andadapted to be 'connected kwith the opposite ends of a sawV blade, power`driven means for reci-procating'said belt, and means for automati-Vcally stopping said power driven means if the saw blade should break orbecome disconnected, said last-named means comprising a latch pivotallyconnected withv a fixed Y support and a tripping device for said latchsecured uponfsaid belt. Y

8. ig saw comprising a machine frame, a belt supported by said frame andadapted to .beV connectedwith the opposite ends of a saw blade, powerVdriven means' for reciprocating said belt, and means for automaticallystopping said power driven means if the saw blade should break or becomedisconnected, said last-named means comprising a latchpivotallyconnected with a fixed support and tripping device for said latchad'ustabl secured uoon said belt. l l l l l' v u 9. A jig saw comprisinga machine. trame,

i a belt supported by said frame and adapted to be connected with theopposite ends oit a saw blade, means i'or maintaining Vsaid beltconstantly under tension, power driven means for reciprocating saidbelt, and means for stopping said power driven means if the saw bladeshould break or become disconnected, said last-named means comprising alatch pivotally connected Vwith a fixed supl port.` and a trippingdevice for said leversecured upon said belt. l i

10. In aV jig saw, the combination ofv a Vtrame, a belt supportedthereby and vadapted `to be connected to the opposite ends of a sawblade, guides for the saw blade, powerdriven means or'reciprocating thesaw blade, a latch pivotally connected with a Y {iX-ed supportand havingan opening in one end through which said 'belt' freely reciprocates,power-controlling means normally held in engagementk with the' other,end of thelatch, and an abutmentv carriedV by said belt and adapted tocontact and turn said latch for disengaging it from saidpowercontrolling means for stopping the. operation of the .machine il'the saw blade should break or become disconnected.

-, 11.111 ajigsaw, the coinbinationof a framea vbelt supported 'thereby'and adapted Y to be connected toV the `opposite ends of a sawblade,`guides lfor the saw blade, powerdriven means for reciprocating the ,saw

blade,a coupling member secured to said:

tojbe connected with'the oppositeiends of:

a saw blade, a spring for n'iaintaining said belt constantly undertension, power driven means for reciprocating said belt, and meansactuated by said spring for stopping said .power-driven.means if the sawblade should A break or become disconnected. Y 13 A saw comprising amachine frame, a belt supported `lby saidframe Vand adapted to beconnect-edwith the-opposite ends ofa saw blade, a spring forVmaintaining said* belt underconstant tension,la motor, means AIdrivenby said motor for reciprocatingsaid belt, a switch orcontrolling the`operation so Y of said motorfand means actuated by said spring upon thebreaking of a saw blade for .the disconnection thereof, for operatingsaid switch to stop the motor.

WILLIAM a. Fiati?.

